The invention relates to a cartridge having a propellant-charge casing and an electrothermal ignition device, with the propellant-charge casing being connected to a metal casing base.
In these known cartridges, the propellant-charge powder is ignited through the formation of arc discharges inside the propellant-charge powder of the respective cartridge. To this end, at least one wire conductor is located inside the propellant-charge powder of the respective cartridge. To ignite the powder, a high current flows through the conductor, causing the corresponding wire to vaporize explosively. The light arc formed in this process then ignites the surrounding propellant-charge powder.
A cartridge of this type is known from, for example, DE 199 36 649 A1, Here, a well-insulated electrical contact piece is guided through the metallic casing bottom or floor, the piece protruding far beyond the outside of the floor or bottom piece of the casing base and being contacted by a high-voltage electrode on the side of the gun. Inside the casing base, the contact piece is supported laterally by a fairly solid insulating molded part, and is connected to a contact disk, to which a plurality of wire conductors that are led through the propellant-charge powder are secured.
One drawback of this known cartridge is that the contact piece protruding on the outside cannot be used to implement an automatic operation of the corresponding weapons system, particularly with wedge-type breechblocks. Moreover, the solid, insulating molded part that supports the contact piece occupies a relatively large amount of space inside the cartridge, which is counter to the requirement of a high charge density of the propellant-charge powder.
It is the object of the invention to provide a cartridge that can be produced simply, and permits an automatic operation of weapons systems, as is also fundamentally possible in the use of conventional cartridges.
This object generally is achieved according to the present invention, by a cartridge having a propellant-charge casing and an electrothermal ignition device, with the propellant-charge casing being connected to a metal casing base having an opening in the bottom of the base, and having an insulating layer disposed in the casing base and resting in a form-fit against an entire inside surface of the casing base and forming a casing floor. The insulating layer has an annular portion that protrudes into the opening of the casing base, with the annular portion having an outer surface supported against an inside wall of the base bottom defining the opening. An electrical contact piece is disposed in and surrounded by the annular portion of the insulating layer and protrudes from the inside of the casing base to enable electrical contact by a high-voltage electrode from an exterior of the casing base. The electrical contact piece is connected in one piece to a contact disk, which rests in a form-fit against the insulating layer formed as a casing floor, and is connected to ignition wires of the electrothermal ignition device. Further especially advantageous embodiments of the invention are disclosed.
The invention is essentially based on the concept of forming the contact piece such that it does not protrude past the front surface of the floor or bottom piece on the outside, and on the inside, it forms the contact disk, which is supported over a large surface area against the propellant-charge easing by a relatively thin-walled insulator that is formed as a cartridge floor, so a correspondingly solid, insulating molded part can be omitted.
The cartridge according to the invention, in which the insulation of the high-voltage-conducting parts are completely integrated into the casing base, is especially well suited for modern tank cannons having a wedge-shaped breechblock.
Whereas, in the cartridge known from DE 199 36 649 A1, parts of the weapons-system breechblock are also required for supporting the electrode and the insulator under gas pressure (i.e., during firing), in the cartridge of the invention, the electrode and the insulator are completely supported by the casing base of the cartridge.
It has proven advantageous for the outer edge of the contact disk to be formed as a sealing lip, so powder gases are prevented from traveling between the insulator and the contact disk during firing.
For securing the contact disk, it is possible to glue the disk to the insulator and then glue the insulator to the casing base.
In a further advantageous embodiment of the invention, the sealing lip of the casing base and the insulator are formed in one piece. In this case, the process of vulcanizing the insulating layer simultaneously produces the connection (adhesion) to the casing base and the contact disk. As has been seen, this method is well suited for mass production of the cartridge of the invention.
Further details about and Advantages of the invention ensue from the exemplary embodiments explained below in conjunction with figures.